792 ANIMAL HEAT. 
rhynchus anatinus) from 24° - 4 to 25 0- 2. In the case of birds the 
temperature is generally two or three degrees higher than that of 
mammals. 
In the observation of the temperature of animals, it is necessary, 
if comparable results are to be obtained, to insert the thermometer 
to a similar extent each time, and to prevent struggling of the animal 
before and during the time of observation. Finkler 1 found that the 
rectal temperature of guinea-pigs was 36°T, 38° - 7, and 38° - 9, at a depth 
of 2 - 5, 6, and 9 cms. respectively. Aronsohn and Sachs 2 found 
that the rectal temperature of normal rabbits rose to over 40° after 
a short chase, Hobday 3 observed a rise to 41 0- 1 in the case of sheep 
and pigs, and Mott 4 has noticed a rise of one or two degrees in the 
temperature of monkeys, owing to a similar cause. Moreover, the times 
of observation should as far as possible be similar, for animals show 
a daily variation in temperature. Rabbits extended on their backs and 
tied down lose so much heat that their temperature rapidly falls 
(Legallois, Richet.' 5 ) 
The temperature of cold-blooded animals. — It has already been 
shown that there is no hard and fast line between the so-called warm-blooded 
animals — those with a constant temperature, and the cold-blooded animals — 
those with a varying temperature. Further proofs of this will now be given, 
and others will be brought forward when the subject of hibernation is 
considered. 
John Hunter 6 made some interesting observations upon the temperature 
of bees. He found in the month of July, when the temperature of the air was 
12 0, 2, and a north wind was blowing, that the temperature at the top of a hive 
full of bees was 27°"8. In December the temperature of the hive was 22 0, 8, 
when that of the external air was only 1°"7. A single bee has so little power 
of keeping itself warm, that it quickly becomes numb and almost motionless 
when exposed to the moderate cold of a summer night. The aggregation, 
however, of vast numbers in a hive ensures the production of enough heat to 
keep the bees active even in winter, and for this production of heat a constant 
supply of food is necessary. The warmth of the hive is needed also for 
the eggs, pupa?, and larva?, for Hunter found that they would not live in a 
temperature of 17°. The wax is by means of the warmth kept so soft that the 
bees can model it with ease. . 
Numerous observations upon the temperature of bees were made by 
Newport, 7 who found that, when the insects were in a state of activity, 
their temperature was above that of their surroundings ; the larva and pupa 
had a lower temperature than the imago, and less power of generating as well 
as of maintaining their temperature. In winter the temperature of a hive, 
when the bees were in a state of repose, fell considerably, and varied slowly 
with that of the atmosphere ; the bees did not become torpid, but passed into 
a deep sleep, broken at intervals by periods of activity. A very low atmo- 
spheric temperature aroused the bees, and thus prevented any great fall in the 
temperature of the hive. Thus on January 2, 1836, at 7.15 a.m., when the 
temperature of the air was -7 0, 5, that of the hive was -l°'l, and the bees were 
quiet, but after the bees were disturbed by tapping the hive, the temperature 
1 Arch. f. d. cjcs. Physiol., Bonn, 1882, Bd. xxix. S. 117. 
2 Ibid., '1885, Bd. xxxvii. S. 232. 
3 Juurn. Comp. Path, and Therap., Edin. and London, 1896, vol. ix. p. 286. 
4 Note communicated to the writer. 
5 Rev. sclent., Paris, 1884, tome viii. p. 300. 
6 "Works," Palmer's edition, London, 1837, vol. iv. p. 427. 
7 Phil. Trans.. London, 1837, pt. 2, p. 253. 
